Mold for casting crankshafts



` 21, D. CAMPBELL l MOLD FOR CASTING CRANKSHAFTS vFiled Jan. 6, 1937 12 Sheets-Sheet 1 2N VEA/TOR Feb. 21, 1939. 11.1. CAMPBELL 2,147,880

' vMOLD FOR CASTING ORANKSHAFTS Filed Jan. 6, 1937 12 Sheets-Sheet 2 Y Domd d. Camplae Bafwww A TTORNE YS Feb. 2l, 1939. D. J. CAMPBELL y2,147,880 i MOLD FOR CASTING CRANKSHAFTS Filed Jan. 6, 1937 12 Sheets-Sheet 3 A TTORNE YS MOL-D FOR CASTING CRANKSHAFTS VFiled Jan. Gf` 1937 l2 Sheets-Sheet 4 r BY Y @mj A TTORNE ys Feb. 21, 1939. D. J, CAMPBELL Y' 42,147,880

MOLD FOR'ASTING GRANKSHAFTS Filed Jan. 6, 1957 12 ShetS-Sheet 5 11e-fg- '-ll- I/ ATTORNEY Feb. 2K1, .1939. D. `lfcxMPBriLJ. 2,147,880.l

MOLD FOR lJASTING CRANKSHAFTS Filed Jan. 6l, 1937 l2 Sheets-Sheet G PF1-Q u1 [N VENTOR ,BY @o dCAmML 21 TToR/VE Ys FebQzl, 1939. DJ. CAMPBELL 2,147,880

MOLD FOR CASTING CRANKSHAFTS Filed Jan. 6, 1957 12k Sheets-Sheet 7 A TTORNE YS Feb. 21, 1939. l D J CAMPBLL v2,147,880

MOLD FOR CASTING GRANKSHAFTS Filed Jan. 6p v193'? l2 Sheets-Sheet 8' J2 /4 sa /N VENTOR Dona d. Cambba my Feb. 21, 1939. D. J. CAMPBELL v 2,147,880

MOLD FOR CASTING CRANKSHAFTS Filed Jan. 6, 1937 12 Sheets-Sheet 9 zz .l

INVENTOR MMM A TTORNE YS Feb. 21, 1939. l D 1 CAMPBELL 2,147,880

MOLD FOR CASTING CRANKSHAFTS Filed Jan. 6, 1937 12 Sheets-Sheeft. 10

[N VEA/'TOR 65 DOBH d. CamPMl Feb, 21, 1939.

D. J. CAMPBELL MOLD FOR CASTING CRANKSHAFTS Filed Jan. 6, 1937 l2 Sheets-Sheet l1 A TTORNEYS Feb. 21,/1939. D; J. CAMPBELL MOLD FOR CASTING oRANKsHAFTs l2 Sheets-Sheet 12 Filed Jan. 6 193'? NVENTOR Cambbe aux TTORNEY 73 BY Damm d.

` Patentes Feb. 21, una

UNITED STATES grasso I Mom soacasmd camsmir'rs Donald I. Campbell, Spring Lake Township,

f. y.Ottawa County, Mich.

'Application January 6, 1937, Serial No. 119,226

This invention relates to crankshaft molding and is primarily concerned with a novel mold and method of producing/fthe same for casting engine crankshafts or similararticles of what may be 5 termed tortuous andirregular shapes, and generally of an elongated character.

Crankshafts for internal combustion engines are produced in very large amounts. Such shafts contain bearings for the shaft and others for the connecting rods which are interposed between the shaft and the pistons of the engine. The connecting rod bearings'are oiset from the longitudinal axis about which the shaft turns. lZihere are transverse connecting portions or flanks bel5 tween the several connecting rod bearings, the

bearings of the crankshaft itself, and counterweight portions'for absorbing and eliminating vibration` vas much as possible. The crankshafts have generally heretofore been made by forging y suitable steel billets for such purpose, but I have e for some time been casting such crankshafts by pouring a suitablmolten metal into mold cavities having the shape of the crankshafts to be produced. Usually the metal is of a cast iron alloy, relatively low in carbon and containing varioust alloying elements such as chromium, nickel, molybdenum and the like, the specific composition of the metal comprising no part of the present invention. f

With my invention I make up the molds in a series of substantially horizontal sections placed one over the other, each of said mold sections belng made from-sand and iluid mixture baked to a relatively hard consistency. The dividing lines 3 5 betweenthe several sections cause the finished casting to have fins at such places which must be removed in the completed crankshaft. One object and purpose of the present invention is to provide a mold wherein any such fins as are thus @produced are in every case located on parts of the cast crankshaft between bearing portions thereof, so that nobearing portion has any thin radial vfinsprojecting 'therefrom which would necessarily havefto be ground or otherwiserremoved in finishing the bearingsof the crankshaft. The removal of said fins yWhere the same are on the bearing portions of the crank shaft is a tedious and expensive operation vrequiring special grinding wheels and. special operations. Where the iinsuare/ on parts interposed between the bearings such asfonthe flanks, counterweighty portions and any-other connecting' members b etween adjacent bearing portions the saine may be very quickly and leasily rough ground and re moved, with an elimination of a considerablepart a single crankshaft.

of the expense connected with the nishing of the shafts.

There are many other. objects and purposes of the present invention, such as the production of a mold by means of which a plurality of the 5 crankshafts may be cast at one time together with novel structure for conducting the molten metal tothe crankshaft mold cavities and controlling the flow of the molten metal thereto so as to cause no breaking'of parts of the mold b el 0 cause of impact of the molten iron thereagainst in passing or falling from the upper end of the mold to the lower ends or intermediate portions of the mold cavities. And further, for supplying intermediate the ends of the molds and, therel5 fore, intermediate the ends of the crankshaft,v feeder means for supplying molten metal to countteract shrinkage of the metal in cooling in addition to feeder cavities at the upper end of such mold cavities for the same purpose. 20

These andmany other objects and purposes will be 'apparent upon an understanding of the invention had from the following description, taken in connection with the accompanying drawings, in which, 25

Fig. 1 is a vertical section of a built-up sectional mold made in accordance with my invention.

Figs. 2 to 12, inclusive, are vertical sections `taken diagonally through the several sectional parts of the mold, said'secti'onal parts when used 30 being positioned vertically one overand resting upon another as has been shown in Fig. 1.

Fig. 13 is a plan View of the upper end cover for the mold when al1 of the sections have been `as sembled` and are found together.

Figs. 14 to 24, inclusive, are plan views of the several sections of the mold shown in Fig. l.

Fig. 25 is a perspective view showing acompleted Amold and the apparatus and method used" for securing and holding the several sections Vof* 4 0 the mold together. -f

Fig. 26 is a perspective viewl illustrating the method whereby theseveral sections of the mold are disposed and located in proper alinement with respect to each other, -in which "position 45 they are provided with securing andl-v binding means illustrated in Fig. 25. i

Fig. 27 is an elevation 'ofa crankshaft which" may be made in accordance with the method and by the moldapparatus of the presentinvention. 50 Fig.' 28 is a vertical section of a; mold forcasting "5 Fig.` 29 is a fraginentarv'vertical transverse y section showing the essential parts{o fa` molding,"- machine whereby the sections of the "moldyjaren 55 made by the use of compressed air, the section being taken substantially on the plane of lines 28--23 oi Fig. 30, and

Fig. 30 is a plan View of the intermediate member located between the flask and the sand carrying hopper of such apparatus.

Like refe :ence characters refer to like parts in the diierent iigures of the drawings.

The mold comprises a plurality of'sections to II, inclusive, as shown in Fig. 1 disposed one upon the other, the section I being the uppermost section, the section |I the bottom or base section and the sections 2 to I0, inclusive between. The uppermost section I (Figs. 2 and 14) is substantially square in outline and in its upper part and to one side thereof has a pouring basin I2 into which molten iron may be delivered with a horizontal runner I3 leading therefrom to a vertical centrally positioned sprne opening I4 which extends through the seci `ion i and at its lower end joins with an enlargement I5. In this form of the invention four crankshafts are to be cast. The mold section I is provided with four feeder cavities I8 located around and spaced radially from the central sprue I4. The feeder cavities are reduced somewhat at their lower end and join with a circular disk-shaped cavity I1 located one at the lower end of each of the feeder cavities I8 and at the horizontal lower side of said section I.

The next section 2 of the mold (Figs. 3 and 15) in its upper portion is recessed to receive a complementary core section I8 which is set in the recess and has its upper side ush with the upper side. of the. section 2. At the center of this second section 2 at the lower part thereof is a central vertical opening I9 in alinement with the opening I4. In the upper part of the central portion of the section 2 the opening .is enlarged, as indicated at 20, in order that a skim gate 2| may be disposed therein with its upper side flush with the upper side of the inserted core section I8. When the section I is placed upon the section 2 as shown in Fig. 1, the enlargement I5 at the lower end of the opening I4- is directly over the skim gate 2| through which there are a large number of small openings for passing the molten iron, checking its speed and preventing the passage of dirt particles, scale and the like.

Also,'in the upper side of the part I8 is a shallow recess 22 smaller in diameter than the recess I1 directly above it but in axial alinement therewith. Extending downwardly from the shallow recess 22 is a circular opening or cavity 23 which, a short distance above the lower side of the part I8 joins with a cavity 24, the sides of which diverge downwardly and outwardly from the lower end of the opening 23 to the bottom side of the core part I8. Below the cavities 23 and 24 are vertical central cavities 25 extending nearly to the lower side of the section 2 and joining with;

shallow cavities 28 which are of the same shape as and arecomplementary to and cooperate with cavities 28 in the upper side of thel next lower section 3 whereby when iron fills the two cojoining cavities 28 and 23 transverse iianks of the crankscribed Join with`\vertical bearing cavities 23 Y which extend through the section 3and which at their lower ends connect with the'cavities 30 in the lower side of said section 3, the same being complementary to and of the same shape as mold cavities 3l in the upper side of the next lower section 4. Said next section 4 has vertical bearing cavities 32 connecting with the cavities at 3| and passing vertically through the mold Section (Figs. 5 and 17). The cavities at 30 and 3| are of the shape shown in Fig. 17. At the central part of the section 4 is a short vertical opening 83 which has four branches 34 leading downwardly outwardly therefrom and at right angles to each other connected by means of gates 35 with cavities 38 in the lower side of the section 4 and which are connected with the cavities 3| in the upper side thereof by the vertical bearing cavities 32.

The next lower section 5 (Figs. 6 and 18) has a central opening 38 therethrough in axial alinement with the openings 21, I9 and I4. At its upper end are radial gates 31 connecting with shallow cavities 39 in the upper side of the section 5 which are of the same shape and in conjunction with the cavities 36 previously described at the underside of the section 4. Vertical bearjoining with shallow cavities 44 in the lower side of the section 8. At the center and in the upper side of the section 8 is a recess 38a which when the mold is assembled is located directly below the lower end of the opening 38 through the section 5 and which provides a lower closed end for the mold sprue, the metal poured (Fig. 1) passing through the skim gate 2| following through the openings I9, 21 and 33 and passing through the gates 34, 35 and 31 laterally to the crankshaft mold cavities. The enlarged gates 34 hold a relatively large body of molten metal and provide, when filled with the molten metal, feeders o1 metal to the intermediate portion of the cast crankshafts to compensate for shrinkage.

Section 1 to be placed next above the section 8 has an auxiliary core section 45 located in the upper part thereof similar to the auxiliary section I8 at the upper side ofthe section 2. An enlarged opening 48, one for each of the crankshafts to be cast, is made through said auxiliary core section 5. The counterweight vibration absorbing part of the crankshaft which is cast in\ the cavities 48 has a projecting ange made byv the metal cast into the recess at 41. The divid-v ing line between the sections 1 and 45 is across this ilange as shown, so that in the upper part of the section 1 there are complementary shallow recesses which when the two sections are together as shown in Figs. 8 and 20. make a single large cavity 48. At the lower side of this cavity and in the upper side of the recessed portion of the section 1 are cavities 48 to serve as locating recesses for metal cores which are located one in each oi' the cavities 48 and around which the `molten metal passes in the casting operation,

thereby avoiding undue shrinkage. A bearing cavity 43 extends nearly through the section 1 and joins with a shallow cavity SII-in the lower side of the section 1 as shown in Fig. 8, one for each of the four crankshafts to becast.

The succeeding lower cavity 8 has shallowcavities of the same outline and contour as the drical bearing cavities 52 extend from the shallow cavities 5| (Figs. 9 and 21) nearlyv through the section 8 and join with shallow cavities 53 in the lower sides thereof. 'I'he next lowermost section 9 (Figs. 10 and'22) have shallow cavities 54 in their upper sides ofl the same shape and in direct alined conjunction with the cavities 53 previously described in the lower side of the section 8. Vertical cylindrical bearing cavities 55 extend from the cavities 54 vdownwardly through the section 8 and join with shallow cavities 56 in the lower side of the section 9.

The next lower section Il] (Figs. ll and 23) has cavities 51 in its upper side of the same shape and form as the shallow cavities 56 in the lower side of the section 9 and j oin therewith. Vertical cylindrical openings 58 extend downwardly from the cavities 51 Iand join'at their lower ends with shallow cavities 59 in the lower side of the section I0. 1

'I'he lowermost section II has shallow cavities 6D (Figs. 12 and 24) in its upper side corresponding in shape and outline with the cavities 59 in the lower side of the section I0. From these cavities vertical bearing cavities 6I extend downwardly partly through the section II so that the mold cavities for each of the four crankshafts which are to be cast end a distance above the lower side of the section II.

The various sections of the mold after they have been made from core sand and baked to a relatively hard consistencyare assembled one over the other as shown in Fig. 1 to make a stack and metal cores 62 are located in the cavities 48 as previously stated. The method of assembling the several sections I to inclusive, is shown in Fig. 26. A trough having upwardly and outwardly diverging sides 63 has supporting feet 64 whereby it may be placed upona horizontal oor. The sections are then disposed in proper relative position to each other and brought together as shown in Fig. 26. A bottom frame `or pan 65 is placed against the lower end of the lowermost section I and a covering frame 66 placed against the upper end of the uppermost section I. At the corners of these bottom and cover frames are lugs -spaced apart from each other whereby rods 61 may be placed between the lugs at the three exposed corners of vthe mold sections. The rods 61 are provided withheads at their lower ends and are threaded at their upper ends to receive thumb nuts. By attaching and partially tightening three of the rods and thumb nuts the mold sections are secured together and then the fourth and remaining rod 61 and the thumb nut thereon is put in place and tightened. The upper cover member 66 has an opening 68 therein lined with fire clay at 69 corresponding to the pouring basin I2, runner I3 and vertical sprue opening I4, in the upper side of the upper section I.

In Figs. 29 and 30 the way in which the various mold sections are produced is shown. For each section there is a flask 10 of a size, shape and depth corresponding `to the section which is to bernade. Fonexahiple, in Fig. 29 the flask 10 therein is for making the lower section II. Patterns 1I are located and permanently secured on the bottom of the ask. In the bottom of the flask are small openings 12 coveredby screens 13. The patterns 1| correspond to the cavities 6| and 60 which are'to be made in the upperside of the mold section Il. A hopper 141s designed in the molding machine which is used to carry .the

sand for the mold section. At its lower side it is closed by a bottom secured in piace as shown. Interposed between the bottom ofthe hopper and the upper side of the flask 1li 'is a plate 16 which has oppositely extending ears 11 with locating pins .18 for properly positioning the plate upon the flask 10 by passing the pins through guiding bushings therefor carried by horizontally projecting ears on the flask directly below the ears 11 on the plate 16. A plurality of sleeves 19 are formed integral with the plate 16 and extend upwardly' having central vertical openings 88 therethrough which are adapted to come into conjunction Withsimilar openings 8| made in the bottom 15 of the hopper. The plate 16 is also provided with a plurality of air escape openings 82 covered with a screen 83. The sand is forced through the openings 8| and 80 into the flask and around the patterns 1|, air escaping through the openings 12 and 82 while the sand is held substantially from escaping by the screens 13 and 83. There may be some sand collect at the upper part of the plate 16 but this can be blown ofi' by projecting a current of compressed air against it. The sand is pressed to the desired density by the action of the compressed air and after the ilask is filled the hopper 14 is turned to one side the plate 16 removed, and the flask inverted and withdrawn from the mold section which has been made. It is, of course, to be understood that there will be different patterns and asks used for each of the mold sections to be made and that in most cases it will be necessary that parts of the patterns be carried at the upper side of the bottom of the flask 10 at the lower side of the plate 16. In a days or a weeks run of the crankshaft casting, a very large number of the sections machine is changed to use a different flask 10 and 0' a different plate 16 for the next section and so on until the required number of each of the sections for making up a predetermined quantity of molds have been made. l

In Fig. 28 a mold is shown for the production of a single crankshaft, the sections Ia to IIa, inclusive, being positioned vertically one on the other and the crankshaft mold cavity extending generally in a vertical direction from the upper end of the mold to the lower end thereof Where it terminates .a short distance above the bottom of the lowermost section IIa. Pouring the metal is at the upper end of the feeder cavity I6 in the upper section Ia and there is no central sprue with gates leading to several crankshaft mold cavities vas in the structure shown in Fig. 1. The auxiliary core sections I 8a and 45a are used in the sections 2a, and 1a in the same manner and for the same purpose as previously described with respect to the auxiliary sections I8 and I4 the main sections 2 and 1.

Between the sections 3a and 4a and the sections Ba and Illa the mold cavities are modified and somewhat so as to lie at an angle to the horizontal division lines between the several sections I to Il or la to lla, inclusive. fins appear, indicated at Il in Fig. 27, by reason of the molten metal having a tendency to attempt to penetrate between the adjacent faces o! the contiguous sections. These iins are readily chipped, led or ground or otherwise removed. There are no ns on any ot the bearing portions of the crankshaft. This greatly reduces the cost of completing and rendering the cast shaft suitable for use in engines.

The invention which has been described is one in continuous practical use for the production or cast crankshafts for engines which are more and more coming into extensive use. The invention is denned in the appended claims and is to be considered comprehensive of all forms of structure coming within their scope.

I claim:

1. A mold for crankshafts comprising, a plurality of horizontally disposed mold sections stacked one upon another, a portion oi said sections having a mold cavity extending through the sections into which molten metal is to be Apoured to produce the crankshaft, the division lines between the horizontally disposed mold sections being transverse to the mold cavity beyond the ends of any parts thereof in which bearings of the crankshaft are cast. v

2. An elongated mold for casting crankshaits comprising, a plurality of horizontally positioned mold sections disposed on top of each other and of such varied thicknesses that iins, resulting from the casting operation, will appear either at the ends or beyond the ends of each bearing section, a plurality of feeder cavities in the upper mold section, said upper mold section also having a pouring basin. a centrally positioned sprue opening, and a runner connecting said basis and sprue opening, said sprue opening extending downwardly and'ln alinement with openings in a plurality of lower mold sections forming a vertical passageway therethrough.

DONALD J. CAMPBELL. 

